Construct validity of Advanced Practice Role Delineation tool: A confirmatory factor analysis

Abstract Aim To test the psychometric properties and latent structure of the modified Strong Model of Advanced Practice tool. Background The Strong Model of Advanced Practice tool, developed in the United States in 1990s and its Australia modification, has been increasingly used to delineate nursing and advanced practice nursing roles. Few research‐driven efforts to develop and validate these tools have taken place. Design Psychometric testing of the modified Strong Model of Advanced Practice tool. Methods A confirmatory factor analysis was undertaken to examine the factors of the modified Strong Model of Advanced Practice tool and compare the model to the Australian Advanced Practice Role Delineation tool. The data were collected in September 2020. Results The analysis of the data provided construct validity evidence of the underlying theoretical structures of the five‐factor modified Strong Model of Advanced Practice tool. The 45‐item modified Strong Model of Advanced Practice tool demonstrated satisfactory, slightly better psychometric properties and construct validity than the 40‐item Advanced Practice Role Delineation tool. Conclusions Psychometric properties of the scale were evaluated and reported. Based on the statistical analysis, we suggest the use of the 45‐item modified Strong Model of Advanced Practice tool.


Summary statement
What is already known about this topic?
• The Strong Model of Advanced Practice and its modifications have been increasingly used to delineate nursing and advanced practice nursing roles.
• Few research-driven efforts to develop and validate these tools have taken place.
What this paper adds?
• The analysis of the data provides construct validity evidence of the underlying theoretical structures of the five-factor modified Strong Model of Advanced Practice tool.
• The tool demonstrates satisfactory, slightly better psychometric properties and construct validity than the 40-item Advanced Practice Role Delineation tool.
The implications of this paper: • The validated modified Strong Model of Advanced Practice tool may be utilized to develop, standardize and delineate various nursing and advanced practice nursing roles within healthcare organizations.
• Based on statistical analysis, we recommend the use of a 45-item Modified Strong Model of Advanced Practice tool.

| INTRODUCTION
Countries are continuously developing clinical nursing and advanced practice nursing (APN) roles to respond to changing practice and healthcare demands. The clinical career ladder, from registered nurse (RN) to advanced practice nurse, has gained interest in several countries. Nurse managers, nursing associations and policy developers are required to consider the variability of nursing roles in human resource management. These premises highlight the need for validated tools to examine and distinguish the generalist, specialist and APN roles. The Advanced Practice Role Delineation (APRD) tool (Gardner et al., 2016), a modification of the Strong Model of Advanced Practice (SMAP) tool (Ackerman et al., 1996), has been increasingly used in several countries during the past few years. It has been found to be useful in the identification of advanced practice nursing activities and domains of practice. A recent content validation study resulted in the development of the 45-item modified Strong Model of Advanced Practice (MoSMAP) tool in Finland.
In this paper, we will report the findings of a construct validity study of this tool.

| Background
Registered nurses (RNs), specialist nurses (SNs) and advanced practice nurses form a continuum of nursing roles according to the career structure from RN to advanced practice nurse. While RNs and SNs have diploma or bachelor level education and work at the generalist/ specialist level, advanced practice nurses are post-graduate educated, with extensive experience and advanced competency in the patient, clinical nursing leadership, organizational and scholarship spheres (Jokiniemi et al., 2019) Advanced practice nurses manage the care of complex populations by offering expert clinical care to patients, support the learning of nurses and interdisciplinary team, and facilitate innovation and health system outcomes according to their individual job descriptions (Fulton et al., 2019;Jokiniemi et al., 2020;Lewandowski & Adamle, 2009). Delineation of the role of the advanced practice nurses benefits the clarification of nursing roles, guides role descriptions, strengthens performance and role evaluations and informs the activities of optimal health system utilization (Jokiniemi et al., 2018).
The SMAP tool (Ackerman et al., 1996) was developed in the United States in the 1990s to differentiate and assess the level of APN activity by nurses in the areas of direct comprehensive care, support of systems, education, research, publication and professional leadership. An Australian research team developed the APRD tool, a 41-item modification of the SMAP tool within the Australian context in the 2010s (Chang et al., 2010(Chang et al., , 2012. The APRD tool has consequently been used by several researchers in several countries to investigate nursing and APN roles (Carryer et al., 2018;Gardner et al., 2016;Woo et al., 2019). In addition to the APRD tool, two further modifications of the SMAP tool exist: a 38-item tool developed in Spain (Sevilla Guerra et al., 2018) and a 45-item modification developed in the Finnish context.
Although the SMAP, APRD tool and their modifications have been used extensively in the past few years, there is limited research testing the content or construct of these tools. Within Australia, the APRD modification was developed based on a content (Chang et al., 2010) and a construct validation study (Chang et al., 2012). Based on these studies, one item (medical diagnosis) was omitted from the original tool; however, no new items were added to the tool. In Spain, as a result of a content validation study, a 38-item modification of the APRD tool was developed and an additional construct validity study supported a six-factor structure of the modified 38-item tool (Sevilla Guerra et al., 2018). In Finland, the Australian 41-item APRD tool content was explored by an expert panel to validate its content in the Finnish context in 2020. Based on the content validity study, one item (medical diagnosis) was omitted, and five new items were added, resulting in a 45-item MoSMAP tool. Table 1 summarizes the studies validating the SMAP tool and its international modifications.
The increased use of the SMAP and APRD tools in recent years highlights a global need for a valid tool to differentiate and examine the role activities of advanced practice nurses. Within this study, we tested and reported construct validity research to examine the 45-item Finnish MoSMAP tool. Confirmatory factor analysis (CFA) was used to establish the best-fitting model to the proposed 45-item, five-factor model. A comparison for the 41-item, five-factor APRD tool (Gardner et al., 2016) was also conducted.

| Aim
The aim of this study was to conduct a CFA test on the MoSMAP tool to test the psychometric properties and latent structure of the tool.
The items within the MoSMAP scale are hypothesised to have at least modest inter-correlations, and the tool should measure several distinct qualities with clustering corresponding to the five subscales (APN domains) (Ackerman et al., 1996) of direct comprehensive care: support of systems, education, research, publication and professional leadership (Prudon, 2014).

| Design
A psychometric study with an online, 45-item MoSMAP tool was trialled using CFA to verify the number of underlying dimensions of the instrument (factors) and the pattern of item-factor relationships (factor loadings) (Brown, 2015).

| Participants
A census sample of six Finnish healthcare district nursing personnel was recruited through the organizations' contact persons. To be eligible for this study, the participants had to be (a) a RN/midwife, (b) a SN or (c) an advanced practice nurse. In total, 1497 responses were analysed in this study.

| Data collection
Participant recruitment and data collection were conducted in September 2020. Data were collected using an online self-report questionnaire. The 45-item MoSMAP measured the nurses' activities during a typical month on a 5-point Likert-type scale (0, never; 1, rarely; 2, sometimes; 3, often; and 4, always). Five role domains of direct comprehensive care (support of systems, education, research, publication and professional leadership) form the organizing framework of the scale (Ackerman et al., 1996).

| The tool and its translation
A 45-item MoSMAP tool, which contains the 41-item Australian APRD tool (excluding the item 'makes a medical diagnosis'), was used in this study. The 41-item APRD tool is described in detail by Gardner et al. (2016). Initially, the 41-item APRD tool was translated from English to Finnish and back-translated from Finnish to English by two independent authorized translators of a professional transla-   Cronbach's alpha score of a coefficient for the 40-item APRD-tool was 0.90, and for the modified 45-item tool 0.92.

| Pilot testing of the tool
The surveys were piloted with participants who met the inclusion criteria of the study (n = 5). Feedback was requested regarding the clarity and understanding of the language, survey functionality and time burden, as well as appropriateness of the length of the survey.

| Data analysis
The Statistical Package for the Social Sciences (SPSS, 2017) version 25 and IBM SPSS Amos 27 were employed to conduct CFA and calculate α coefficients. The sample size of 1497 in our study was adequate for CFA (Kline, 2015). In addition, data were missing completely at random (P > 0.05) based on Littles' Missing Completely at Random (MCAR) test (Allison, 2002). No data was imputed, as with the Amos program, as analysis can be performed with missing data (Arbuckle, 2016

| Ethical considerations
The ethical aspects of the research were evaluated by the University

| Construct of the modified Strong Model of Advanced Practice
In the 45-item MoSMAP tool, a five-factor model was retained for the final CFA solution. The tool factors included the same items as the 41-item APRD tool, with the exception of the removal of item 'makes a medical diagnosis'. Based on the modelling, one item, 3.6. 'provide appropriate patient and family education', was moved to factor 1 (domain 1), direct comprehensive care. The item shift was also supported by an exploratory factor analysis item factor loading, which were checked for consistency with the CFA results.

| Confirmatory factor analysis for the modified Strong Model of Advanced Practice
The model was specified based on a theoretical model developed for CFA. The results are reported with standardized regression coefficients of the items related to the latent variables. The model is presented in graphic form (Figure 1).
The MoSMAP model indices proved to be satisfactory. The range of the standardized factor loadings were moderate to high (0.252-0.820), supporting convergent validity. Factor covariances may be seen in Table 2. For item regression weights, please see supporting information (Table S1). A CFI of 0.907 and TLI of 0.892 were considered very good, and a CMIN/DF score of 5.08 and RMSEA value of 0.52 were both considered good (Brown, 2015).
The 41-item APRD model was also applied. Model fit was quite good; however, the MoSMAP model indices proved satisfactory with slightly stronger values than the 40-item tool, indicating that the 45-item tool fits better for our data.
F I G U R E 1 Confirmatory factor analysis of modified properties and ability to measure advanced practice nursing activities.
Due to the content validation of the tool, it may better reflect the contemporary healthcare environment with the items added to support of systems (n = 3) and education domain (n = 2). Similar to some other countries, the item 'makes a medical diagnosis' was removed from the MoSMAP tool due to the item not being in the scope of nurses' practice (Chang et al., 2010). However, if needed, it may be readded to the tool.
Overall, the fit statistics suggest that the estimate model repro- As the empirical and conceptual foundations of the SMAP/APRD (which have only minor differences) are getting stronger due to increased use and research, we emphasize the use of CFA in future studies to guide the specification and evaluation of the factor models used. EFA is typically used earlier in the process of scale development and construct validation, whereas CFA is used in later phases to confirm the underlying structure established with prior empirical (EFA) and theoretical grounds. As there are specifications made in regard to the number of latent factors and the pattern of relationships between them within the SMAP and APRD, CFA can provide compelling evidence of the convergent and discriminant validity of these theoretical constructs (Brown, 2015).